Generally, the DNS zone file is for "domain.tld" and not for "www.domain.tld."
The SOA record is for the entire zone file for "domain.tld" which includes all its sub-domains, including the www subdomain.
To better use the DNS checking tool, use the domain and not the www sub-domain.
Using your example, this would be "_______.org" instead of "www._______.org"